The present invention relates to a bookbinding apparatus having a trimming apparatus for trimming and cutting the outer edge of a bunch of sheets subjected to bookbinding processing, and more particularly, to improvements in trimming mechanism without staining the cover surface finished in book form.
Generally, such a type of trimming apparatus presses a bunch of sheets against a paper mount such as a table by a pressing mechanism to hold, and in this state, trims the outer edge of the bunch of sheets. As trimming of a bunch of sheets, for example, the apparatus performs trimming cut to trim and align three sides of a bunch of book-bound sheets or cuts a predetermined portion of a bunch of sheets to separate and cut to ½, ⅓ or the like, and such an apparatus has been known widely.
In thus trimming a bunch of sheets, when the sheets are cut using a flat-shaped trimming blade in a shape with a length corresponding to a width of the sheets, there are known a cutting mechanism in which a fixed blade is provided opposite to the trimming blade, and two these cutting edges act in scissors form, and another cutting mechanism in which a blade receiving member in cutting-board form is disposed in a position opposite to the trimming blade.
Conventionally, an apparatus for opposing a trimming blade and blade receiving member to cut is disclosed in, for example, Patent Document 1 (Japanese Unexamined Patent Publication No. H10-119000). The Document discloses the apparatus for cutting sheets mounted on a paper mount by up-and-down movements of the trimming blade. In this case, in the paper mount is embedded a soft material forming a blade receiving surface for receiving a cutting edge of the trimming blade. Polyurethane rubber is proposed as a material for the blade receiving material.
Further, as a similar mechanism, Patent Document 2 (Japanese Unexamined Patent Publication No. 2004-114198) proposes an apparatus where a blade receiving member is formed in the shape of a roll using a soft material and axially supported by an apparatus frame rotatably, and whenever a bunch of sheets is cut by a trimming blade, the roll is rotated a predetermined amount.
[Patent Document 1] Japanese Unexamined Patent Publication No. H10-119000
[Patent Document 2] Japanese Unexamined Patent Publication No. 2004-114198
As described above, when a bunch of sheets is trimmed by a flat-shaped trimming blade, it has already been known that a blade receiving member is made of a soft material to prevent a cutting edge of the trimming blade from wearing. In this case, when cutting is repeated using the trimming blade for a long time, it is known that a flaw occurs in the blade receiving surface of the blade receiving member and interferes with subsequent trimming. Therefore, conventionally, Patent Document 2 proposes forming the blade receiving member in the shape of a roll, and rotating the member a predetermined angle whenever cutting.
However, when a bunch of sheets to trim is a booklet subjected to glue bookbinding using an adhesive or case work, in the conventional method of rotating the blade receiving member at a predetermined pitch irrespective of trimming sides in cutting an upper-edge portion or lower-edge portion where the adhesive exists on the trimming end surface, and cutting a fore-edge portion where the adhesive does not exist, the cover surface may be stained in cutting the fore-edge portion. This is caused by the fact that the adhesive of the previously cut upper-edge portion or lower-edge portion adheres to the blade receiving surface and remains, and when the adhesive is in a semi-dry state, the adhesive is bonded to another bookbinding cover in a finish stacker, and thus results in failure in bookbinding, concurrently with staining. Particularly, when the upper-edge portion and lower-edge portion are trimmed, since the spine portion of the bunch of sheets is bonded using the adhesive, trimmed paper pieces are also bound. Therefore, when the upper-edge portion and lower-edge portion are trimmed, the paper debris drops from the blade receiving surface in a cluster under its own weight. In contrast thereto, in the fore-edge portion, since trimmed paper pieces are separate, when the adhesive adheres to the blade receiving surface, trimmed paper pieces may be bonded to the blade receiving surface and remain. When the remaining sheets are detected by a trimming jam sensor as a jam, the apparatus is halted.
The inventors of the invention noted that the adhesive that adheres to the blade receiving surface and remains results in a cause of a stain, etc. in subsequent trimming, the fore edge end is thereby stained in trimming the fore-edge portion, and that bookbinding quality thus remarkably deteriorates, and reached the idea of distinguishing between a blade receiving area in trimming the upper-edge portion or lower-edge portion and a blade receiving area in trimming the fore-edge portion to set in the blade receiving member.
It is a main object of the invention to provide a bookbinding apparatus having a trimming apparatus that does not stain a fore edge end by an adhesive adhering to a blade receiving surface in trimming a bunch of sheets subjected to bookbinding using the adhesive.
Further, it is another object of the invention to provide a bookbinding apparatus enabling increases in durability of a blade receiving member opposed to a trimming blade to trim a bunch of sheet.